1. Field of the Invention
The present invention relates to the preparation of bleached vegetable pulps, more especially vegetable pulps destined for nutritional use, by bleaching same with hydrogen peroxide in an aqueous alkaline solution.
By "vegetable pulps" are intended the pulps of beets, sugar beets and others, citrus fruits and fruits such as peaches, pears, apples, apricots, oleaginous plants, such as sunflowers, cereals, such as wheat, corn or oats, legumes, such as garden peas, etc., remaining after the primary desired product, such as sugar, fruit juice, pectin, oil, starch, flour, has been extracted therefrom by any known means, e.g., by water-extraction.
These pulps, designated the extracted pulps, which constitute the basic vegetable material processed according to the present invention, shall hereinafter sometimes be referred to simply as "pulps", without any further definition.
They are characterized by a high food fiber content, as determined by the enzymatic method well known to this art.
2. Description of the Prior Art
The vegetable pulps have heretofore been used for the preparation of food supplements and products, for example cereals. But the commercial success of such products has unfortunately been hindered by the excessive coloration thereof.
To alleviate this problem, it has been proposed to this art to bleach such pulps by treating them with hydrogen peroxide in an aqueous alkaline solution, for example as described in U.S. Pat. No. 4,241,093. However, even if the treatment with the hydrogen peroxide is preceded by a washing of the pulp in an acid medium using a decolorizing agent, such as sulfur dioxide, this results in merely lightening the pulp, for example from gray to yellow in the case of beet pulps, as indicated in FR 2,382,866.